Spectral studies on copper(II) complexes of biologically active
glutathione
Deo Nandan Kumar
a
, Bibhesh Kumar Singh
a
, Bhagwan Singh Garg
a,
*,
Pramod Kumar Singh
b
a
Department of Chemistry, University of Delhi, Delhi 110007, India
b
Department of Chemistry, Kirori Mal College, University of Delhi, Delhi 110007, India
Received 19 June 2002; received in revised form 29 August 2002; accepted 30 August 2002
Abstract
Copper(II) complexes of reduced glutathione (GSH) of general composition Na[Cu(L)(X)] ×
/
nH
2
O (where LH
2
0
/
GSH; X 0
/
Cl
(
,NO
3
(
, NCS
(
,CH
3
CO
2
(
, HCO
2
(
, ClO
4
(
and n 0
/
0 Á
/
4) have been prepared and characterized by
elemental analysis, magnetic susceptibility measurements, IR spectroscopy, EPR spectroscopy and ligand-field
spectroscopy. The EPR and ligand field spectra in the solid state suggest planar geometry for all the complexes.
# 2002 Elsevier Science B.V. All rights reserved.
Keywords: Copper(II) complexes; Glutathione; EPR spectroscopy; IR spectroscopy; Ligand-field spectroscopy
1. Introduction
Glutathione (GSH, g-glutamate Á
/
cysteine Á
/
gly-
cine) is the most common cellular non-protein
thiol [1] in the cell, it exists predominately in the
reduced form (GSH) at concentrations of 0.1 Á
/
10
mM and is readily oxidized to the disulfide
(GSSG) [2]. Among GSH roles are to protect cells
from reactive oxygen intermediates, UV radiation
and heavy metal toxicity [3]. In the latter case,
GSH scavenges and sequesters heavy metal ions by
coordinating them through its sulfydryl, thereby
inhibiting their binding to proteins and nucleic
acids [1,4 Á
/
7]. Coordination of GSH may also
facilitate transfer to metal binding proteins, such
as metallothionein. In some cases, GSH reduces
metal ions, such as Pt(IV) anticancer drugs, to
species that coordinate or otherwise react with
DNA [7 Á
/
10]. On the other hand, coordination of
Pt(II) by GSH is thought to be a contributing
factor to cisplatin resistance by tumor cells [11,12].
GSH affects the type of DNA binding occurring in
cells [13]. [Pt(dien)I]
'
and its hydrolyzed product
exhibits any kinetic preference toward the nucleo-
tide over the thiols at physiological pH, even if
excess nucleotide is employed [14].
The influence of arsenic on GSH content, the
level of GSH in blood and tissues of mice detected
in acute and subchronic experiment [15]. The
* Corresponding author. Tel.: '
/
91-98111-41062; fax: '
/
91-
766-6250.
E-mail address: deonandan2002@rediffmail.com (D.N.
Kumar).
Spectrochimica Acta Part A 59 (2003) 1487 Á
/
1496
www.elsevier.com/locate/saa
1386-1425/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
doi:10.1016/S1386-1425(02)00303-7